So I heard somewhere else on here that a marriage outside of a catholic church is not valid, so having sex in that marriage is a mortal sin. What? That dooms much of the planet who is not catholic, any married person not catholic, so is this really the case? Please explain this to me. Thanks!
A Catholic is bound to marry with approval of the Church so that is true for a Catholic. Non Christians have what is called a natural marriage. Between the baptized, a sacramental marriage is formed, and is the celebration follows the form of the non-Catholic church or ecclesial community, but, if it is not properly formed as lifelong, exclusive, and granting the gift of conjugal relations, it would not be valid.
That’s not correct. The Catholic Church recognizes marriages outside the Catholic Church. If the marriage is between two baptized parties it is sacramental; if one or both parties are unbaptized it is a natural marriage.
I think you may be conflating marriage laws regarding Catholics with those regarding non-Catholics.
Catholics must be married according to Catholic form. This means the marriage must be witnessed by a priest or deacon or there must be a dispensation. A Catholic who ignores these laws is not in a valid marriage; a non-Catholic is not held to the same standard.
But there is far more to this issue than the pure legalism presented thus far.
As Christ told us, he did not come to condemn but to save.
With that thought in mind, a non-sacramental marriage can be brought into compliance with Church teaching on this important sacrament through convalidation.
See your pastor!
Actually a non-sacramental marriage becomes sacramental when both parties are baptized. Until/unless that happens it will never be sacramental, it will be a natural marriage. Two Jews, for example, can have a perfectly valid natural marriage and there’s nothing wrong with that.
An invalid marriage involving a Catholic can be made valid through convalidation or radical sanation. But again, Catholic rules on marriage apply to Catholics, not to non-Catholics.